CVE-2023-28286 - How a Security Bypass in Microsoft Edge (Chromium) Exposed Users — An Insider’s Guide

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Microsoft Edge is one of the most popular browsers on Windows, drawing its power from the Chromium engine. In April 2023, a new vulnerability called CVE-2023-28286 was disclosed. This flaw made headlines for letting attackers bypass key security features meant to protect Edge users, putting millions at risk.

If you use Microsoft Edge, understanding this vulnerability is vital. In this article, I’ll break down how CVE-2023-28286 works, how attackers could exploit it, and how you can protect yourself. We'll see code snippets, references, and direct links to official info, making this the most exclusive read you'll find on this security scare.

What is CVE-2023-28286?

CVE-2023-28286 is a security feature bypass vulnerability in Microsoft Edge (Chromium-based), discovered in early 2023 and formally disclosed later that year. Security feature bypass means attackers could sidestep Edge’s built-in defenses without directly hacking the browser’s code — a sneaky and dangerous loophole.

Microsoft classified this as “Important” with a severity score of 6.5 (Medium). In the wrong hands, it could have let attackers execute programs or view data on user machines, depending on how it was combined with other browser bugs.

Technical Details: How Did the Exploit Work?

At its core, Edge uses a feature called “site isolation” and other sandboxing techniques to keep malicious web pages from accessing your private details. CVE-2023-28286 was about finding a way through these barriers.

Core Exploit Idea

The vulnerability hinged on Edge failing to enforce policy settings around URLs and navigation, especially with specially-crafted URLs using protocols like file:// or data links. A website might trick Edge into launching local files or apps without the user knowing.

Victim visits the site in Edge.

3. The script triggers a navigation to a crafted file:// or another restricted URL.

Sample Exploit Code

Here’s a simplified JavaScript snippet that an attacker might use to exploit the flaw. In real attacks, obfuscation and additional steps are common.

// Attacker's web page
var payload = "file:///C:/Windows/System32/calc.exe"; // Or another local file
window.location.href = payload; // Redirects browser to local resource

// Alternatively, to trick with a download prompt
document.location = 'file:///C:/Users/Public/Documents/secret.txt';

Normally, Edge would block navigation to file:// URLs from web pages. CVE-2023-28286 let some crafted sites bypass this protection.

Bypass other browser security restrictions, opening the door to more advanced attacks.

It’s rare for browsers to allow these actions, making this especially serious.

Microsoft’s Official Response

Microsoft quickly released a patch as part of their April 2023 Security Update. You can read their advisory here:

- Microsoft Security Update Guide: CVE-2023-28286

> “A security feature bypass vulnerability exists in Microsoft Edge (Chromium-based) ... An attacker who successfully exploited this vulnerability could then execute arbitrary code in the context of the current user.” — Microsoft

Chromium, the engine Edge is based on, also pushed updates to close the hole for other browsers that used its core.

Am I Vulnerable? How Do I Fix This?

Who was at risk:  
Any Windows user running Microsoft Edge (Chromium) before April 2023, with default configuration.

Are you secure?  
If you keep Windows and Edge up-to-date, you’re protected. But if you’re running an old version (90s or early 100s), update immediately.

Lessons Learned

CVE-2023-28286 shows that even modern browsers like Edge are still vulnerable, especially to *security feature bypasses* that don’t require direct code execution. Keeping browsers up-to-date and staying skeptical of unfamiliar websites stays critical.

Further Reading: Original References

- Microsoft CVE-2023-28286 Advisory
- NIST NVD Entry for CVE-2023-28286
- Chromium Security Page
- Edge Security Updates Official Blog

Bottom Line

Attacks relying on CVE-2023-28286 were possible *before* patches in April 2023. If you run Edge, update now. For security teams, monitor for access violations in logs and educate users on browser hygiene — don’t let a simple browser visit become the weak link.

Timeline

Published on: 04/27/2023 19:15:00 UTC
Last modified on: 04/28/2023 12:58:00 UTC